rcu: Add tracing to irq/NMI dyntick-idle transitions (bd2b879a) · Commits · e / devices / android_kernel_teracube_emerald

include/trace/events/rcu.h

+8 −6

Original line number	Diff line number	Diff line
		@@ -421,16 +421,18 @@ TRACE_EVENT(rcu_fqs,

		/*
		* Tracepoint for dyntick-idle entry/exit events. These take a string
		* as argument: "Start" for entering dyntick-idle mode, "End" for
		* leaving it, "--=" for events moving towards idle, and "++=" for events
		* moving away from idle. "Error on entry: not idle task" and "Error on
		* exit: not idle task" indicate that a non-idle task is erroneously
		* as argument: "Start" for entering dyntick-idle mode, "Startirq" for
		* entering it from irq/NMI, "End" for leaving it, "Endirq" for leaving it
		* to irq/NMI, "--=" for events moving towards idle, and "++=" for events
		* moving away from idle. "Error on entry: not idle task" and "Error
		* on exit: not idle task" indicate that a non-idle task is erroneously
		* toying with the idle loop.
		*
		* These events also take a pair of numbers, which indicate the nesting
		* depth before and after the event of interest. Note that task-related
		* events use the upper bits of each number, while interrupt-related
		* events use the lower bits.
		* and interrupt-related events use two separate counters, and that the
		* "++=" and "--=" events for irq/NMI will change the counter by two,
		* otherwise by one.
		*/
		TRACE_EVENT(rcu_dyntick,

+6 −0

Original line number	Diff line number	Diff line
		@@ -880,12 +880,15 @@ void rcu_nmi_exit(void)
		* leave it in non-RCU-idle state.
		*/
		if (rdtp->dynticks_nmi_nesting != 1) {
		trace_rcu_dyntick(TPS("--="), rdtp->dynticks_nmi_nesting,
		rdtp->dynticks_nmi_nesting - 2);
		WRITE_ONCE(rdtp->dynticks_nmi_nesting, /* No store tearing. */
		rdtp->dynticks_nmi_nesting - 2);
		return;
		}

		/* This NMI interrupted an RCU-idle CPU, restore RCU-idleness. */
		trace_rcu_dyntick(TPS("Startirq"), rdtp->dynticks_nmi_nesting, 0);
		WRITE_ONCE(rdtp->dynticks_nmi_nesting, 0); /* Avoid store tearing. */
		rcu_dynticks_eqs_enter();
		}
		@@ -1057,6 +1060,9 @@ void rcu_nmi_enter(void)
		rcu_dynticks_eqs_exit();
		incby = 1;
		}
		trace_rcu_dyntick(incby == 1 ? TPS("Endirq") : TPS("++="),
		rdtp->dynticks_nmi_nesting,
		rdtp->dynticks_nmi_nesting + incby);
		WRITE_ONCE(rdtp->dynticks_nmi_nesting, /* Prevent store tearing. */
		rdtp->dynticks_nmi_nesting + incby);
		barrier();